Electrical apparatus.



A. B. REYNDERS &. J. E. MATEER.

ELECTRICAL APPARATUS. APPLICATION FILED MAY 13, 1909.

Patented Aug. 6, 1912.

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NVEN 0R5 WITNESSES:

A. B. REYNDERS &. J. E. MATBER.

ELECTRICAL APPARATUS APPLICATION FILED MAY 13, 1909.

Patented Aug. 6, 1912.

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WITNESSES ATTORNEY A. B. REYNDERS &. J. E. MATEER.

ELECTRICAL APPARATUS.

APPLIOATION FILED MAY 13, 1909.

Patented Aug. 6, 1912.

3 SHEETS-SHEET 3v INVENTORS 8 2:51 BY 72f ATTORNEY WITNESSES UNITED STATES PATENT OFFICE.

ARTHUR B. REYNDERS AND JESSE E. MATEER, OF WILKINSBURG, PENNSYLVANIA,

ASSIGNORS TO WESTINGHOUSE ELECTRIC CORPORATION OF PENNSYLVANIA.

AND MANUFACTURING COMPANY, A

ELECTRICAL APPARATUS.

To all whom it may concern.

Be it known that We, ARTHUR B. REYNDnns and JESSE E. MATEER, both citi- Zens of the United States, and residents of \Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Apparatus, of which the following is a specification.

Our invention relates to transformers and to other electric apparatus, and it has for its object to provide improved insulation by which the coils and leads of transformers and similar apparatus may be particularly adapted for very high voltages and the space occupied by the transformer, or other apparatus, be materially reduced.

For very high-voltage service, bushings of the so-called condenser type have been successfully utilized for insulating the leads of transformers, circuit-breakers and other devices from the metal cases in which the devices are contained.

According to our present invention, we have adapted this type of insulation to various other purposes by maintaining any predetermined distribution of stress in the insulation irrespective of the thickness of the insulating layers and the areas of the condenser plates.

Figure 1 of the accompanying drawings is a partially sectional elevation of a transformer constructed in accordance with our invention. and Fig. 2 is a detail view, on a larger scale, of a portion of the winding and insulation shown in Fig. 1. Fig. 3 is a view, corresponding to Fig. 2, of a modified structure which lso serves to illustrate our invention.

Referring to Figs. 1 and 2 of the drawings, the device here illustrated comprises a substantially rectangular magnetizable core member 1, the longer sides of which are preferably cruciform in cross-section, a sec ondary winding 2, insulating sleeves 3 and 4 and a primary winding comprising a plurality of coils .5 which surround the crueiform sides of the core. outside of the sleeves 3 and 4. The transformer is inclosed in a metal tank or casing 6 which may or may not be filled with oil or other suitable insulating liquid and the high-voltage leads 7 Specification of Letters Patent.

Application filed May 13, 1909.

Patented Aug. 6, 1912.

Serial No. 495,771.

and 8 are provided with insulating bushings 9 and 10 that project through, and are supported by, a removable cover 11. The highvoltage coils 5 are divided into two groups 12 and 13 which are connected to each other and to ground at one end, as shown in Fig. 1 of the drawings, the leads 7 and 8 being connected to opposite ends of the respective groups.

The insulating sleeves 3 and 4 are built up of alternate layers of conducting and insulating materials (see Fig. 2) and the lengths of the several layers are so calculated as to form a series of steps directly within the coils 5 of the high-tension winding. The innermost layers of the sleeves extend substantially the entire length of the sides of the core member and the outer layers are relatively short. The layers of conducting material are relatively thin and are successively connected, from the outside inwardly, to taps from the highest-voltage coils of the winding groups to the lowest. By this means, the strains imposed upon the insulating sleeves are positively determined and may be made to correspond to the quality and thickness of the insulating material of which each layer is composed. It is evident that the potential of each of the conducting layers is absolutely independent of the thickness of the insulation and of the area of the conducting layer instead of being dependent upon both these factors as is the case in the so-called condenser type insulation having no connections to the conducting layers.

The static leakage from the edges of the thin conducting layers may be materially reduced by means of conducting rings 14 of circular cross-section disposed at the ends of the insulating layers in contact with the conducting layers, as shown inFig. 2. Rings having a relatively large sectional diameter are preferably used with the high-voltage layers, and rings having smaller sectional diameters may be used where the voltage is less.

Each of the bushings 9 and 10 is preferably built up of alternate layers of conducting and insulating materials and the ends are tapered to increase the creepage distance between conducting layers, which preferably correspond in number, and are connected to, the conducting layers of which the sleeves 3 and t are composed. The inner layers of the bushing are, of course, connected to the outer layers of the sleeve, since the potentials of these layers are more nearly commensurate.

The two groups of high-voltage coils 12 and 13 may be sufiiciently separated from each other and from the walls of the tank or casing 6, if the relative size of the core member 1 and the tank will permit, to obviate the necessity for any insulation other than that provided by the fluid in the tank. If the transformer is to occupy a minimum space, however, the coil groups 12 and 13 should be surrounded with insulating sleeves which are built up and connected in a manner similar to that employed in the construction and connections for the sleeves 3 and 4.

Referring to Fig. 3 in which like parts are designated by the same reference characters, only the outer conducting layers of the sleeves 3 and 4 are here connected to intermediate points in the high-voltage winding, the inner layers being utilized under these conditions for the purpose of electrically separating the low-voltage coils of the high-voltage winding, from the core. This is obviously unnecessary where the neutral point of the high-voltage winding is grounded, as shown in Fig. 1.

Only the higher-voltage points in the bushing are connected to corresponding potential points in the sleeve 3 since the insulation is ample for the lower volt-ages even if the stresses introduced vary over relatively wide limits.

It is evident that variations in the circuit connections for the transformer and in the size and arrangement of arts may be effected without departing t fom the spirit of our invention, and we desire that only such limitations shall be imposed as are indicated in the appended claims.

We claim as our invention:

1. In a transformer, the combination with a magnetizable core, a winding in inductive relation thereto, and an insulating sleeve located between the winding and the core and comprising a plurality of concentric cylinders of conducting material connected to intermediate points in the winding and insulating cylinders alternating therewith, of a casing in which the core and windings are disposed, a terminal bushing supported by the casing and comprising concentric cylinders of conducting material and insulating cylinders alternating therewith and electrical connections between the conducting cylin ders of the bushing and those of the insulating sleeve.

2. In a transformer, the combination with a magnetizable core, a winding in inductive relation thereto, an insulating sleeve located between the winding and the core and comprising a plurality of concentric cylinders of conducting material connected to intermediate points in the winding and interleaved insulating cylinders, of a casing in which the core and windings are disposed, a terminal bushing supported by the casing and comprising concentric cylinders of conducting material and interleaved insulation, and electrical connections between the conducting cylinders of the bushing and those of the insulating sleeve, said cylinders being connected in accordance with their respective relations to the casing and to the core.

3. The combination with two insulating bodies severally comprising alternate layers of insulating and conductlng materials, of means for electrically connecting the normally equi-potential points of said bodies.

4. The combination with an electric conductor and two insulating bodies for different portions thereof, of means for efi'ecting a corresponding distribution of stress in said bodies.

5. The combination with an electric conductor of relatively high potential, and a plurality of insulating bodies severally comprising alternate layers of insulating and conducting materials, of electrical connectors between corresponding conducting layers of said insulating bodies for equalizing the distribution of stress therein.

6. In a transformer, the combination with a magnetizable core, a winding in inductive relation thereto, an insulating sleeve located between the winding and the core and comprising a plurality of concentric cylinders of conducting materials and interleaved insulating cylinders, of a casing in which the core and windings are disposed, a terminal bushing supported by the casing and comprising concentric cylinders of conducting material and interleaved insulation, and connectors between the conducting cylinders of the bushing and those of the insulating sleeve.

7. In a transformer, the combination with a core, a winding, an insulating body located between the core and the winding and comprising a plurality of alternate layers of conducting and insulating material, and a casing in which the transformer is disposed, of a terminal bushing extending through the casing and supported thereby and comprising concentric cylinders of conducting material and insulation, and means for connecting the conducting layers of the insulating body which are adjacent to the winding to intermediate points therein and to the conducting cylinders of the bushing which are adjacent to the winding terminal.

8. The combination with two insulating bodies of the condenser type, of connections between said bodies for equalizing the potential strains therein.

9. The combination with two insulating subscribed our names this 4th day of May, bodies of the condenser type, of connectors 1909.

, between the corres onding conducting plates of said bodies that? are adjacent to the high potential members with which they are associated, for equalizing the stresses through- Witnesses: out their higher-potential portions. F. CREEDY,

In testimony whereof, we have hereunto B. B. Hmns. 

